Kamen Rider S36 E27 Case27: Play

Under a fierce assault from a mysterious Rider who appeared out of nowhere, Baku is jolted awake from his dream. Who is this person capable of changing the future? Baku sets himself the mission to "uncover the enemy’s true identity." Meanwhile, at CODE, Zero and Three grow increasingly alarmed by the appearance of "Sieg." Who exactly is "Sieg"…!?